I. Field of the Invention
The present invention relates generally to surgical drapes. More particularly, the present invention relates to a disposable surgical drape for use in cardiovascular surgical procedures which advantageously maintains sterile and clean conditions at an operation site and may optionally be used to isolate a sterile pumping mechanism from a non-sterile pump driving mechanism and/or provide support for medical equipment used during cardiovascular procedures.
II. Discussion of the Prior Art
Surgical drapes are well known in the medical community. Generally speaking, surgical drapes are designed to prevent contamination of the sterilized operative site. The need for surgical drapes stems from the inherent risk for infection during surgical procedures. More specifically, bacteria on the patient's skin and/or from unsterilized equipment may infect the surgical site. In order for the bacteria to infect the wound, it must be transferred by a medium such as airborne particles, fluids, lint, dust particles or skin particles originating from the surgeon or patient or any other staff in the operating theatre.
A wide variety of surgical drapes have been developed in the prior art to improve sterility at the operative site. In certain applications, multiple drapes are employed to reduce the possibility of infection, including the use of a surgical drape deployed about the head/neck region of the patient. In this fashion, surgical support staff (such as a perfusionist) may be positioned on the non-surgical side of the drape partition while the surgical team operates within the sterile field on the other side of the surgical drape.
There are two main types of surgical drapes: disposable and reusable. Disposable surgical drapes are typically constructed of multiple layers, with one layer having absorbent properties and another layer that is impervious to fluids. In this fashion, the disposable surgical drape provides both absorbency and a bacterial barrier.
Reusable surgical drapes are typically constructed of cotton fabric. Cotton surgical drapes are advantageous in that, during a surgical procedure, any spilled fluids will be readily absorbed by the drape. As will be appreciated, this eliminates the fluid as a transport medium for bacteria. However, bacteria may nonetheless pass through the fibers forming the cotton drape, and fibers may become detached from the drape, presenting the possibility for bacteria to enter the operative site. To avoid this problem, the drapes have been constructed from a polyester-cotton mixture treated with a liquid repellant finish. While an improvement, these newer cotton-based surgical drapes were nonetheless flawed in that the finish loses its liquid repellant characteristics over time. Another drawback to cotton-based surgical drapes is that they are predisposed to produce lint, which thereby provides a transport medium for the bacteria. Moreover, the production of lint increases after each use and reuse.
During surgical procedures, a second drape may be employed as a partition to separate the sterile surgical site from a non-sterile zone outside the field of surgery. When deployed about the patient's head and/or neck, such a drape is referred to as an “anesthesiologist screen” because it separates the non-sterile area where the anesthesiologist sits during surgery from the sterile surgical area below the patient's head and neck. Anesthesiologists typically monitor and seek to control such patient characteristics as blood gas, lung ventilation, body temperature, and evacuation of fluids.
In cardiopulmonary bypass (CPB) procedures, the anesthesiologist is also responsible for establishing and monitoring the bypass circuit. CPB surgery involves the use of a blood pump to remove and return blood from the patient's body through cannulas and tubing placed within the patient's circulatory system. The outflow cannula is connected to a blood pump, such as the one disclosed in U.S. Pat. No. 5,746,575 titled “Blood Pump as Centrifugal Pump,” the disclosure of which is hereby expressly incorporated by reference. The blood pump is driven through the use of a motor that is magnetically coupled to the blood pump. Typically, the motor used to drive the blood pump is not sterilizable such that the motor must be positioned outside the sterile surgical field. By placing the blood pump and motor outside the sterile field, long lengths of surgical tubing must be utilized to connect the blood pump to the cannula. This additional medical tubing increases the priming volume of the CPB circuit and may also increase hemolysis based on the exposure to a greater amount of foreign surface area, i.e. the tubing.
To establish a CPB circuit, medical tubing is passed from the sterile surgical site, under the anesthesiologist screen, for connection to the blood pump and motor driving unit located in the non-sterile region. The anesthesiologist must de-air the system to ensure no air emboli will form in the patient's blood system. After de-airing the system, the tubing is connected to a blood pump, which the anesthesiologist controls with an associated pump control and monitoring system. Throughout the entire procedure, the surgeon must relay control commands to the anesthesiologist and rely upon these communications. The surgeon is typically unable to view the pump or control panel at any time during the procedure.
The CPB circuit described above, while very common in use, is nonetheless flawed in several significant ways. First, this prior art CPB circuit is undesirable because it increases the amount of foreign material that the blood is in contact with, thereby increasing the likelihood of hemolysis. This is due to the need to place the blood pump and motor outside the sterile surgical field. The blood must also be further treated with heparin to reduce the natural clotting that occurs as the result of contact between the blood and the foreign material of the CPB circuit. Another significant drawback of the CPB system of the prior art is that the pump and motor are necessarily placed outside the sterile surgical field (due to the inability to sterilize the motor). With the pump and motor outside sterile surgical field and thus outside the surgeon's field of view, a second person must be present within the operating room to monitor and control the pump and driving motor. This disadvantageously clutters the operating room. Moreover, the information displayed on the CPB equipment must be relayed to the surgeon, thereby further complicating the procedure.
The present invention is directed at overcoming, or at least reducing the effects of, one or more of the problems set forth above.